As a transmission with a friction-gearing mechanism, a so-called “Beier” power transmission (or a so-called “Beier” variator) employing a mechanical drive, which drive includes a plurality of cone disks (input disks) and a plurality of flange disks (output disks), is generally known. One such “Beier” power transmission has been disclosed in FIGS. 3-4 in Japanese published Utility Model application No. 3-2954 (hereinafter referred to as “JU3-2954”).
In the “Beier” power transmission as disclosed in JU3-2954, power, inputted into an input shaft, is transmitted via gears (e.g., an input-shaft gear, splined-shaft gears, and intermediate idler gears each meshing with the input-shaft gear and the associated splined-shaft gear) to a plurality of splined shafts (e.g., three splined shafts), and further delivered equally to a plurality of stacks of cone disks (e.g., three stacks of cone disks) arranged to surround the central flange-disk stack. The cone disks of each stack and the central flange disks are arranged alternately with each other, such that the cone disk is interleaved between the associated two adjacent flange disks. Also provided is an automatic contact-pressure regulation mechanism, which is comprised of a face cam (i.e., a loading cam) and a spring. The face cam and the spring are both installed on an output shaft, in a manner so as to maintain the loading force (the contact pressure) on the disks at all times. The interleaved cone disk sets are coated with oil (traction oil) when operating. At their points of contact, axial pressure applied by the flange disks compresses the oil film, increasing its viscosity. The cone disks transmit motion to the flange disks without metal-to-metal contact by shearing the molecules of the high-viscosity oil film. A speed-change link mechanism is also provided to cause a downshift or an upshift by moving the cone disks radially toward the flange disks (output speed decrease) or away from the flange disks (output speed increase).